Practical quasi parton distribution functions

TL;DR

This paper introduces a method to compute parton distribution functions using lattice QCD by employing quasi distributions, addressing UV divergence issues through subtraction, and demonstrating the matching process at one-loop level.

Contribution

It proposes a subtraction method for power-law UV divergences in quasi distributions, enabling accurate matching with normal distributions on the lattice.

Findings

Successful subtraction of power divergence in quasi distributions

Demonstration of one-loop matching between continuum and lattice

Improved lattice calculation approach for parton distributions

Abstract

A completely new strategy to calculate parton distribution functions on the lattice has recently been proposed. In this method, lattice calculable observables, called quasi distributions, are related to normal distributions. The quasi distributions are known to contain power-law UV divergences arise from a Wilson line in the non-local operator, while the normal distributions only have logatithmic UV divergences. We propose possible method to subtract the power divegence to make the matching of the quasi with the normal distributions well-defined. We also demonstrate the matching of the quasi quark distribution between continuum and lattice implementing the power divergence subtraction. The matching calculations are carried out by one-loop perturbation.